scholarly journals Grass–legume intercropping in integrated crop-livestock systems: a strategy to improve soil quality and soybean yield in the Brazilian Cerrado

2021 ◽  
Author(s):  
Juliana M. A. S. Moraes ◽  
Luiz Gustavo de O. Denardin ◽  
Gabriela C. Pires ◽  
Evelyn C. Gonçalves ◽  
Laércio S. Silva ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Enzymatic Activity ◽  
Soil Quality ◽  
Pigeon Pea ◽  
Brazilian Cerrado ◽  
Organic C ◽  
Soybean Yield ◽  
Soil Microbial ◽  
C And N ◽  
Livestock Systems

Abstract Aims The integrated crop-livestock systems (ICLS) under no-tillage improves soil fertility of the Brazilian Cerrado. We aimed to evaluate the effect of different grass-legume intercropping compared to single grass cultivation in the off-season of an ICLS on (i) soil organic carbon (C) and nitrogen (N) pools, (ii) soil microbial biomass and activity, (iii) soil enzymatic activity, and (iv) soybean grain yield in succession. Methods The field study was conducted in an on-farm experiment in 2016/17 and 2017/18 cropping seasons. The soybean was cultivated in the summer season, with the subsequent treatments in the off-season, using two grasses (Urochloa ruziziensis and U. brizantha), single or intercropped with Cowpea (Vigna unguiculata) or Pigeon pea (Cajanus cajan). We evaluated soil organic C and N pools, microbial biomass and activity, enzyme activity, and soybean yield. Results Cowpea intercropping yielded 24% more soybeans than grasses single cropped. There was a higher microbial biomass and activity, and enzymatic activity in the soil under grass-legume intercropping. In addition to the lower basal respiration and microbial metabolic quotient (qCO2), the greater microbial quotient (qMIC) and microbial biomass C indicate a higher soil microbial C utilization efficiency under grass-legume intercropping. The soil total organic C and N stocks increased under Pigeon pea intercropping by 16% and 27%, respectively, compared to single grasses. Conclusions Grass-legume intercropping in the pasture phase of ICLS is an additional tool to maximize soybean yields in the short term. The intercropping effects on soybean yield were directly related to soil quality improvements through soil biological and biochemical properties.

Management of sugarcane harvest residues: consequences for soil carbon and nitrogen

Soil Research ◽  
2007 ◽  
Vol 45 (1) ◽  
pp. 13 ◽  
Author(s):  
Fiona A. Robertson ◽  
Peter J. Thorburn
Keyword(s):  
Microbial Biomass ◽  
Soil Fertility ◽  
Microbial Activity ◽  
Soil N ◽  
Soil Organic C ◽  
Total N ◽  
Organic C ◽  
Soil Microbial ◽  
C And N

The Australian sugar industry is moving away from the practice of burning the crop before harvest to a system of green cane trash blanketing (GCTB). Since the residues that would have been lost in the fire are returned to the soil, nutrients and organic matter may be accumulating under trash blanketing. There is a need to know if this is the case, to better manage fertiliser inputs and maintain soil fertility. The objective of this work was to determine whether conversion from a burning to a GCTB trash management system is likely to affect soil fertility in terms of C and N. Indicators of short- and long-term soil C and N cycling were measured in 5 field experiments in contrasting climatic conditions. The effects of GCTB varied among experiments. Experiments that had been running for 1–2 years (Harwood) showed no significant trash management effects. In experiments that had been running for 3–6 years (Mackay and Tully), soil organic C and total N were up to 21% greater under trash blanketing than under burning, to 0.10 or 0.25 m depth (most of this effect being in the top 50 mm). Soil microbial activity (CO2 production) and soil microbial biomass also increased under GCTB, presumably as a consequence of the improved C availability. Most of the trash C was respired by the microbial biomass and lost from the system as CO2. The stimulation of microbial activity in these relatively short-term GCTB systems was not accompanied by increased net mineralisation of soil N, probably because of the greatly increased net immobilisation of N. It was calculated that, with standard fertiliser applications, the entire trash blanket could be decomposed without compromising the supply of N to the crop. Calculations of possible long-term effects of converting from a burnt to a GCTB production system suggested that, at the sites studied, soil organic C could increase by 8–15%, total soil N could increase by 9–24%, and inorganic soil N could increase by 37 kg/ha.year, and that it would take 20–30 years for the soils to approach this new equilibrium. The results suggest that fertiliser N application should not be reduced in the first 6 years after adoption of GCTB, but small reductions may be possible in the longer term (>15 years).

scholarly journals SOIL QUALITY IN RELATION TO FOREST CONVERSION TO PERENNIAL OR ANNUAL CROPPING IN SOUTHERN BRAZIL

2015 ◽  
Vol 39 (4) ◽  
pp. 1003-1014 ◽  
Author(s):  
Elcio Liborio Balota ◽  
Ines Fumiko Ubukata Yada ◽  
Higo Furlan Amaral ◽  
Andre Shigueyoshi Nakatani ◽  
Mariangela Hungria ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Microbial Activity ◽  
Soil Quality ◽  
Conventional Tillage ◽  
Soil Disturbance ◽  
Forest Conversion ◽  
No Tillage ◽  
Southern Brazil ◽  
Soil Microbial ◽  
C And N

Many forested areas have been converted to intensive agricultural use to satisfy food, fiber, and forage production for a growing world population. There is great interest in evaluating forest conversion to cultivated land because this conversion adversely affects several soil properties. We examined soil microbial, physical, and chemical properties in an Oxisol (Latossolo Vermelho distrófico) of southern Brazil 24 years after forest conversion to a perennial crop with coffee or annual grain crops (maize and soybeans) in conventional tillage or no-tillage. One goal was to determine which soil quality parameters seemed most sensitive to change. A second goal was to test the hypothesis that no-tillage optimized preservation of soil quality indicators in annual cropping systems on converted land. Land use significantly affected microbial biomass and its activity, C and N mineralization, and aggregate stability by depth. Cultivated sites had lower microbial biomass and mineralizable C and N than a forest used as control. The forest and no-tillage sites had higher microbial biomass and mineralizable C and N than the conventional tillage site, and the metabolic quotient was 65 and 43 % lower, respectively. Multivariate analysis of soil microbial properties showed a clear separation among treatments, displaying a gradient from conventional tillage to forest. Although the soil at the coffee site was less disturbed and had a high organic C content, the microbial activity was low, probably due to greater soil acidity and Al toxicity. Under annual cropping, microbial activity in no-tillage was double that of the conventional tillage management. The greater microbial activity in forest and no-tillage sites may be attributed, at least partially, to lower soil disturbance. Reducing soil disturbance is important for soil C sequestration and microbial activity, although control of soil pH and Al toxicity are also essential to maintain the soil microbial activity high.

Interpretation of microbial biomass measurements for soil quality assessment in humid temperate regions

1999 ◽  
Vol 79 (4) ◽  
pp. 507-520 ◽  
Author(s):  
M. R. Carter ◽  
E. G. Gregorich ◽  
D. A. Angers ◽  
M. H. Beare ◽  
G. P. Sparling ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Plant Growth ◽  
Soil Quality ◽  
Soil Microbial Biomass ◽  
Spatial And Temporal Variation ◽  
Data Set ◽  
K Value ◽  
Organic C ◽  
Soil Microbial ◽  
Temperate Soils

Soil microbial biomass (SMB) measurements are often used in soil biological analysis; however, their interpretation can be problematic. In this review, both the limitations and benefits of indirect (both CHCl3 fumigation incubation and fumigation extraction, and substrate-induced respiration) SMB measurements are outlined, along with their value and interpretation as attributes or indicators to assess some soil quality (SQ) functions (e.g., enhance plant growth, maintain aggregation, regulate energy) for mainly humid, temperate soils, with specific emphasis on research conducted in eastern Canada and New Zealand. Indirect SMB methods are subject to limitations analogous to "soil test" procedures (e.g., soil sampling and handling, water content, storage prior to treatment), and also the difficulties with establishing an acceptable "control" and fraction (i.e., k value) of SMB mineralized or extracted. In many cases, such limitations present a need for some degree of standardization (e.g., pre-conditions of 7- to 10-d incubation at 25°C and −0.001 MPa water potential) prior to SMB measurement. However, for SQ assessment, where "comparative" rather than "absolute" values of SMB are often of interest, use of commonly derived k values seem appropriate for surface soils.Soil ecological factors govern SMB and often underlie much of the spatial and temporal variation in SMB. Plant species composition, mainly through net primary productivity and litter quality, can affect SMB measurements along with trophic cascades in soil, where interactions among soil organisms can influence microbial activity. Benefits of SMB measurements relate mainly to the assessment of both soil C turnover and management induced changes in organic matter. The combination of SMB and δ13C to elucidate the transformations and fate of organic C in cropping and soil management systems has also shown that both temporal and spatial redistribution of C inputs, and soil type (i.e., particle size distribution) are dominant factors in turnover and nutrient flow through the SMB.For SQ assessment, SMB is not a useful indicator for the function of soil as a "medium for plant growth" in regard to plant productivity for intensively farmed temperate soils. For the function of soil to "maintain aggregation", where SMB is one agent only of a multi-faceted process, the relationship between SMB and soil aggregation is not always present and tends to be site-specific. In regard to the "regulate energy" soil function, SMB is related to some degree with decomposition and mineralization processes. The main role of SMB for SQ assessment is to serve within a minimum data set of other indicators (e.g., macroorganic C) to monitor soil organic C storage and change. Key words: Soil microbial biomass, humid climate, soil quality

Effects of conservation tillage farming on soil microbial biomass, organic matter and earthworm populations, in north-eastern Victoria

1990 ◽  
Vol 30 (3) ◽  
pp. 365 ◽  
Author(s):  
PJ Haines ◽  
NC Uren
Keyword(s):  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
Conservation Tillage ◽  
Total N ◽  
Organic C ◽  
Soil Microbial ◽  
North Eastern ◽  
C And N ◽  
Direct Drilling ◽  
Earthworm Populations

A long-term field experiment was set up in 1981 in north-eastern Victoria to determine the effects of conservation tillage farming on agronomic and soil properties. Conventional cultivation was compared with direct drilling, and stubbles retained from the previous crop were compared with burning under direct drilling. Wheat was grown continuously over the 7 years of the experiment. Organic carbon (C), total nitrogen (N), soil microbial biomass and earthworm populations were measured. When samples were taken incrementally down the soil profile, there was a significant concentration gradient of organic matter under direct drilling. In the surface 2.5 cm, biomass C and N, and N mineralisation were 35, 30 and 62% greater, respectively, than under conventional cultivation. Direct drilling into retained stubble did not significantly increase organic C or total N. Of the estimated 7.8 t C/ha added to the soil from conserved crop stubbles, 4% was retained in the top 7.5 cm at the time of sampling. Organic C, total N and biomass C and N decreased with depth in both treatments. Microbial biomass varied considerably with season. The biomass of earthworms in the top 10 cm, under direct drilling, was more than twice that of conventional cultivation, while total worm numbers increased significantly (P<0.05), from 123 to 275/m2, when wheat stubble was retained with direct drilling compared to stubble burning.

Soil microbial biomass, metabolic quotient, and carbon and nitrogen mineralisation in 25-year-old Pinus radiata agroforestry regimes

Soil Research ◽  
2001 ◽  
Vol 39 (3) ◽  
pp. 491 ◽  
Author(s):  
S. Saggar ◽  
C. B. Hedley ◽  
G. J. Salt
Keyword(s):  
Carbon Dioxide ◽  
Microbial Biomass ◽  
Pinus Radiata ◽  
Soil Microbial Biomass ◽  
Negative Influence ◽  
Metabolic Quotient ◽  
Decomposition Rates ◽  
Organic C ◽  
Soil Microbial ◽  
C And N

To understand the effects of agroforestry on soil biological processes we assessed the conditions in Pinus radiata plantations of 50, 100, 200, and 400 stems/ha after 25 years of growth, and in a grassland. Agroforestry resulted in a 15–25% decline in soil organic C and N compared with grassland, and had a significant negative influence on soil microbial biomass. There was less microbial C and N in soils under 50–400 stems/ha of P. radiata than in soils under grassland (0 stems/ha). Soil carbon decomposition and microbial activity were measured by trapping the carbon dioxide produced by incubating soils over a 60-week period. The results showed that soil C decomposition rates were ~1.5 times as much (c. 15 mg CO2-C/kg soil) in soil from grassland as in that from plots with 50 or100 stems/ha (c. 10 mg CO2-C/kg soil), and were further reduced to one half (c. 5.5 mg CO2-C/kg soil) in the plots with 200 or 400 stems/ha. The soils under P. radiata gave off less carbon dioxide per unit of biomass (the metabolic quotient) than soils under grassland. These shifts in microbial biomass and its metabolic quotients appear to be associated with differences in the quantity and ‘quality’ of inputs and soil organic matter decomposition rates, and to reflect the land use change from grassland to forest. Given the general ability of soil microbial biomass to recolonise depopulated areas after tree harvest, we see no problem in restoring populations of these soil organisms vital in controlling nutrient cycling after tree felling, provided adequate adjustments to soil pH are made.

Soil microbial biomass, organic C, and soybean physiology in integrated crop–livestock systems with different inputs

2020 ◽  
pp. 1-13
Author(s):  
Daniele Perreti Bettio ◽  
Ademir Sergio Ferreira Araujo ◽  
Aurenivia Bonifacio ◽  
Fabio Fernando De Araujo
Keyword(s):  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
Organic C ◽  
Soil Microbial ◽  
Livestock Systems

scholarly journals Perennial herbaceous legumes as live soil mulches and their effects on C, N and P of the microbial biomass

2003 ◽  
Vol 60 (1) ◽  
pp. 139-147 ◽  
Author(s):  
Gustavo Pereira Duda ◽  
José Guilherme Marinho Guerra ◽  
Marcela Teixeira Monteiro ◽  
Helvécio De-Polli ◽  
Marcelo Grandi Teixeira
Keyword(s):  
Microbial Biomass ◽  
Soil Depth ◽  
Vegetation Management ◽  
Pueraria Phaseoloides ◽  
Organic C ◽  
Arachis Pintoi ◽  
Factorial Combination ◽  
C And N ◽  
Microbial C ◽  
Macroptilium Atropurpureum

The use of living mulch with legumes is increasing but the impact of this management technique on the soil microbial pool is not well known. In this work, the effect of different live mulches was evaluated in relation to the C, N and P pools of the microbial biomass, in a Typic Alfisol of Seropédica, RJ, Brazil. The field experiment was divided in two parts: the first, consisted of treatments set in a 2 x 2 x 4 factorial combination of the following factors: live mulch species (Arachis pintoi and Macroptilium atropurpureum), vegetation management after cutting (leaving residue as a mulch or residue remotion from the plots) and four soil depths. The second part had treatments set in a 4 x 2 x 2 factorial combination of the following factors: absence of live mulch, A. pintoi, Pueraria phaseoloides, and M. atropurpureum, P levels (0 and 88 kg ha-1) and vegetation management after cutting. Variation of microbial C was not observed in relation to soil depth. However, the amount of microbial P and N, water soluble C, available C, and mineralizable C decreased with soil depth. Among the tested legumes, Arachis pintoi promoted an increase of microbial C and available C content of the soil, when compared to the other legume species (Pueraria phaseoloides and Macroptilium atropurpureum). Keeping the shoot as a mulch promoted an increase on soil content of microbial C and N, total organic C and N, and organic C fractions, indicating the importance of this practice to improve soil fertility.

Distribution of carbon and nitrogen in a long-term cropping system and permanent pasture system

1993 ◽  
Vol 44 (6) ◽  
pp. 1323 ◽  
Author(s):  
FA Robertson ◽  
RJK Myers ◽  
PG Saffigna
Keyword(s):  
Microbial Biomass ◽  
Crop Residues ◽  
Perennial Grass ◽  
Cropping System ◽  
N Availability ◽  
Continuous Cropping ◽  
Organic C ◽  
Soil Microbial ◽  
Permanent Pasture ◽  
Standing Dead

Nitrogen (N) limitation to productivity of sown perennial grass pastures on the brigalow lands of S.E. Queensland contrasts with adequate N supply to annual crops grown on the same soil. In order to understand this anomaly, the distribution of N and carbon (C) under permanent green panic pasture and under continuous cropping with grain sorghum was compared in an 18 month field study. Total soil N and organic C (0-10 cm) were, respectively, 0.37 and 3.20% under green panic and 0.23 and 2.31% under sorghum. Soil microbial biomass (0-28 cm) contained 246 kg N and 1490 kg C ha-1 under green panic and 147 kg N and 744 kg C ha-1 under sorghum. Enhanced microbial growth under pasture was attributed to the continuous input of available C from surface litter and roots. The C/N ratio of pasture residues was high (greater than 50) and conducive to immobilization of N. Availability of N under pasture was further reduced by approximately 50% of plant N being immobilized in standing dead tissue. Under sorghum, the microbial biomass was well supplied with N, but was limited by C availability. The soil under sorghum received a single large C input when crop residues were returned after harvest. The differences in N availability, and hence productivity, of these soils under cropping and permanent pasture were due primarily to differences in the timing and quality of C inputs.

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